Improvement in blackboard-erasers



H. L.ANDREWS.

BLACK-BOARD ERASER.

UNITED STATES PATENT OFFICE.

HERBERT L. ANDREWS, OF CHICAGO, ILLINOIS.

IMPROVEME-NT IN BLACKBOARD-ERASERS.

Specification forming part of Letters Patent No. 190,662, dated May15,1877; application tiled March 1, 1877.

tion of Fig. 1; Fig. 4, a variation.

This invention consists in providing the face of the wood, which formsthe handle of the eraser, with a number of strips of felt, or othersimilar suitable material, to be secured to the block by Wmeans of glue,and without the aid of grooves in providing a continuous strip of thesame material Asecured to the block in the same manner, whichlast-mentioned strip extends over .the ends of the other strips, all ofthestrips having channels or spaces between them, and by making theouter strip continuous these channels, at the ends, are closed, so thatwhile in use the dust which accumulates therein will not escape at theends; and in the peculiar manner, herein described,` of making an eraserreversible.

In the drawings, A represents a block of wood. a are, strips of wovenfelt, or other similar materiahwhich are placed upon their edges, andare glued to the block A. b is a continuous strip of the same material,extending around the other strips a, and across the ends thereof, asshown at d. e are channels or grooves between the strips a, and betweenthe strips a b, and since the strip b extends across the ends of theblock, the channels o are closed at their ends'.

The block. A, as represented, is provided with a groove, e, upon eachside, and B is another block, the central portion of which is entirelycut away, and it is formed as shown in Fig. 3, f being ianges adapted tofit into the grooves e. y

When made in this form, I provide both faces of. the block A with theerasing material-a,l being strips corresponding with a, b being stripscorresponding with b, and c being channels corresponding with o.

When constructed as shown in Fig` 3, af er the material has been worndown on one face, the block A can be removed, turned over, and a seconderaser will be ready for use.

This reversible feature is Ilot essential to my invention. The erasermay be constructed as represented in- Fig. 4, in which C repre sents theblock which forms the handle, to the face of which the strips of erasingmaterial are secured, g corresponding to the strips a, 11,'corresponding to the strips b, and t corresponding to the channels c.

This construction is considerably cheaper than the other, and may bemore generally adopted for that reason.

I am aware that erasers have been made having strips of erasing materialsecured to a block of wood, with channels between the strips; but suchchannels have always been left open at their ends. These channelsreceive a large portion of the dust removed from the board by erasure;and when the channels are open at the ends, as mentioned, this dustescapes therefrom; and with such construction, also, the ends of theerasing material have no support whatever, and are very liable to becomeloosened from the block, or broken down in use; but with myconstruction, the ends of the inner strips are supported and protectedby the continuous strip b.

There is an advantage in securing the erasing material to the block` asdescribed, instead of placing it in groovesin this, that less erasingmaterial is required, as, practically, the whole of the erasing materialcan be worn up.

Where the erasing material consists simply of a series of strips securedto a block Without a continuous strip, the sides of the strips areliable to be broken down in use; but by providing a continuous strip, b,one part supports another, and such strip retains its place until theeraser is completely Worn out.

What I claim as new, and desire to secure by LettersPatent, is asfollows:

1. A blackboarderaser, consisting of a block having strips of felt a, orother similar material, glued to the block, and a strip, b, of the samematerial extending across the ends of the strips, all so arranged as tohave channels c between the several strips, the chanto leave channels cc between the strips, in nels being closed at their ends, substantiallycombination with the block B, all constructed as and for the purposesspecified. and operating substantially ais described.

2. A.reversible blackboard-eraser, consist- HERBERT L. ANDREWS. ing ofthe block A, having strips of felt a a', Witnesses: or other similarmaterial, and strips b b', glued HARVEY S. HAYDEN, to opposite sidesthereof', and so arranged as J. Q. URANDEN BOSET.

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